• Weir is a diversion head work constructed across a river to raise the water level on upstream side.
  • It does not have a storage reservoir.
  • Water is raised up to a required height and water flows over the weir.
  • Weir are also used to measure discharge of water.
  • Barrage is a diversion head work constructed across a river to divert the flow of water.
  • It also doesn't have storage reservoir. Water is raised up to only a few metres.
  • It has adjustable gates installed on top of its crest.
  • Water level in canal is maintained by using these gates.
  • Gates are also opened during flooding season.

Differences between weir and barrage:

Barrage Weir
Low set crest High set crest
Ponding is done by means of gates Ponding is done against raised crest or partly against crest and partly against shutter
Gated over entire length Shutters provided in some parts of length
Gates are of greater height Shutters are of smaller height
Gates are raised up to clear off the high floods Shutters are dropped to pass flood
Perfect control on river flow No control of river in low floods
Gates convenient to operate Operation of shutter is slow and involves labour and time
High floods can be passed with minimum afflux Excessive afflux in high flood
Less silting in upstream due to low set crest Raised crest causes silting in upstream
Longer construction period Shorter construction period
Silt removal is done through undersluices No means for silt disposal
Road or rail bridges can be constructed over it at low cost Not possible to provide road or rail bridge
Costly structure Relatively cheaper structure

Similarities between weir and barrage:

  • They are both used to control floods.
  • Both help in river navigation.
  • Both are used to measure discharge of flow.
Last modified: Sunday, 3 August 2025, 7:35 AM